1 /* 2 * net/sched/sch_mq.c Classful multiqueue dummy scheduler 3 * 4 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * version 2 as published by the Free Software Foundation. 9 */ 10 11 #include <linux/types.h> 12 #include <linux/slab.h> 13 #include <linux/kernel.h> 14 #include <linux/export.h> 15 #include <linux/string.h> 16 #include <linux/errno.h> 17 #include <linux/skbuff.h> 18 #include <net/netlink.h> 19 #include <net/pkt_cls.h> 20 #include <net/pkt_sched.h> 21 #include <net/sch_generic.h> 22 23 struct mq_sched { 24 struct Qdisc **qdiscs; 25 }; 26 27 static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd) 28 { 29 struct net_device *dev = qdisc_dev(sch); 30 struct tc_mq_qopt_offload opt = { 31 .command = cmd, 32 .handle = sch->handle, 33 }; 34 35 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) 36 return -EOPNOTSUPP; 37 38 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt); 39 } 40 41 static int mq_offload_stats(struct Qdisc *sch) 42 { 43 struct tc_mq_qopt_offload opt = { 44 .command = TC_MQ_STATS, 45 .handle = sch->handle, 46 .stats = { 47 .bstats = &sch->bstats, 48 .qstats = &sch->qstats, 49 }, 50 }; 51 52 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_MQ, &opt); 53 } 54 55 static void mq_destroy(struct Qdisc *sch) 56 { 57 struct net_device *dev = qdisc_dev(sch); 58 struct mq_sched *priv = qdisc_priv(sch); 59 unsigned int ntx; 60 61 mq_offload(sch, TC_MQ_DESTROY); 62 63 if (!priv->qdiscs) 64 return; 65 for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++) 66 qdisc_put(priv->qdiscs[ntx]); 67 kfree(priv->qdiscs); 68 } 69 70 static int mq_init(struct Qdisc *sch, struct nlattr *opt, 71 struct netlink_ext_ack *extack) 72 { 73 struct net_device *dev = qdisc_dev(sch); 74 struct mq_sched *priv = qdisc_priv(sch); 75 struct netdev_queue *dev_queue; 76 struct Qdisc *qdisc; 77 unsigned int ntx; 78 79 if (sch->parent != TC_H_ROOT) 80 return -EOPNOTSUPP; 81 82 if (!netif_is_multiqueue(dev)) 83 return -EOPNOTSUPP; 84 85 /* pre-allocate qdiscs, attachment can't fail */ 86 priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]), 87 GFP_KERNEL); 88 if (!priv->qdiscs) 89 return -ENOMEM; 90 91 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 92 dev_queue = netdev_get_tx_queue(dev, ntx); 93 qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx), 94 TC_H_MAKE(TC_H_MAJ(sch->handle), 95 TC_H_MIN(ntx + 1)), 96 extack); 97 if (!qdisc) 98 return -ENOMEM; 99 priv->qdiscs[ntx] = qdisc; 100 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; 101 } 102 103 sch->flags |= TCQ_F_MQROOT; 104 105 mq_offload(sch, TC_MQ_CREATE); 106 return 0; 107 } 108 109 static void mq_attach(struct Qdisc *sch) 110 { 111 struct net_device *dev = qdisc_dev(sch); 112 struct mq_sched *priv = qdisc_priv(sch); 113 struct Qdisc *qdisc, *old; 114 unsigned int ntx; 115 116 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 117 qdisc = priv->qdiscs[ntx]; 118 old = dev_graft_qdisc(qdisc->dev_queue, qdisc); 119 if (old) 120 qdisc_put(old); 121 #ifdef CONFIG_NET_SCHED 122 if (ntx < dev->real_num_tx_queues) 123 qdisc_hash_add(qdisc, false); 124 #endif 125 126 } 127 kfree(priv->qdiscs); 128 priv->qdiscs = NULL; 129 } 130 131 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb) 132 { 133 struct net_device *dev = qdisc_dev(sch); 134 struct Qdisc *qdisc; 135 unsigned int ntx; 136 __u32 qlen = 0; 137 138 sch->q.qlen = 0; 139 memset(&sch->bstats, 0, sizeof(sch->bstats)); 140 memset(&sch->qstats, 0, sizeof(sch->qstats)); 141 142 /* MQ supports lockless qdiscs. However, statistics accounting needs 143 * to account for all, none, or a mix of locked and unlocked child 144 * qdiscs. Percpu stats are added to counters in-band and locking 145 * qdisc totals are added at end. 146 */ 147 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { 148 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping; 149 spin_lock_bh(qdisc_lock(qdisc)); 150 151 if (qdisc_is_percpu_stats(qdisc)) { 152 qlen = qdisc_qlen_sum(qdisc); 153 __gnet_stats_copy_basic(NULL, &sch->bstats, 154 qdisc->cpu_bstats, 155 &qdisc->bstats); 156 __gnet_stats_copy_queue(&sch->qstats, 157 qdisc->cpu_qstats, 158 &qdisc->qstats, qlen); 159 } else { 160 sch->q.qlen += qdisc->q.qlen; 161 sch->bstats.bytes += qdisc->bstats.bytes; 162 sch->bstats.packets += qdisc->bstats.packets; 163 sch->qstats.qlen += qdisc->qstats.qlen; 164 sch->qstats.backlog += qdisc->qstats.backlog; 165 sch->qstats.drops += qdisc->qstats.drops; 166 sch->qstats.requeues += qdisc->qstats.requeues; 167 sch->qstats.overlimits += qdisc->qstats.overlimits; 168 } 169 170 spin_unlock_bh(qdisc_lock(qdisc)); 171 } 172 173 return mq_offload_stats(sch); 174 } 175 176 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl) 177 { 178 struct net_device *dev = qdisc_dev(sch); 179 unsigned long ntx = cl - 1; 180 181 if (ntx >= dev->num_tx_queues) 182 return NULL; 183 return netdev_get_tx_queue(dev, ntx); 184 } 185 186 static struct netdev_queue *mq_select_queue(struct Qdisc *sch, 187 struct tcmsg *tcm) 188 { 189 return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent)); 190 } 191 192 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, 193 struct Qdisc **old, struct netlink_ext_ack *extack) 194 { 195 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 196 struct tc_mq_qopt_offload graft_offload; 197 struct net_device *dev = qdisc_dev(sch); 198 199 if (dev->flags & IFF_UP) 200 dev_deactivate(dev); 201 202 *old = dev_graft_qdisc(dev_queue, new); 203 if (new) 204 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; 205 if (dev->flags & IFF_UP) 206 dev_activate(dev); 207 208 graft_offload.handle = sch->handle; 209 graft_offload.graft_params.queue = cl - 1; 210 graft_offload.graft_params.child_handle = new ? new->handle : 0; 211 graft_offload.command = TC_MQ_GRAFT; 212 213 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old, 214 TC_SETUP_QDISC_MQ, &graft_offload, extack); 215 return 0; 216 } 217 218 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl) 219 { 220 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 221 222 return dev_queue->qdisc_sleeping; 223 } 224 225 static unsigned long mq_find(struct Qdisc *sch, u32 classid) 226 { 227 unsigned int ntx = TC_H_MIN(classid); 228 229 if (!mq_queue_get(sch, ntx)) 230 return 0; 231 return ntx; 232 } 233 234 static int mq_dump_class(struct Qdisc *sch, unsigned long cl, 235 struct sk_buff *skb, struct tcmsg *tcm) 236 { 237 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 238 239 tcm->tcm_parent = TC_H_ROOT; 240 tcm->tcm_handle |= TC_H_MIN(cl); 241 tcm->tcm_info = dev_queue->qdisc_sleeping->handle; 242 return 0; 243 } 244 245 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 246 struct gnet_dump *d) 247 { 248 struct netdev_queue *dev_queue = mq_queue_get(sch, cl); 249 250 sch = dev_queue->qdisc_sleeping; 251 if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 || 252 qdisc_qstats_copy(d, sch) < 0) 253 return -1; 254 return 0; 255 } 256 257 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 258 { 259 struct net_device *dev = qdisc_dev(sch); 260 unsigned int ntx; 261 262 if (arg->stop) 263 return; 264 265 arg->count = arg->skip; 266 for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) { 267 if (arg->fn(sch, ntx + 1, arg) < 0) { 268 arg->stop = 1; 269 break; 270 } 271 arg->count++; 272 } 273 } 274 275 static const struct Qdisc_class_ops mq_class_ops = { 276 .select_queue = mq_select_queue, 277 .graft = mq_graft, 278 .leaf = mq_leaf, 279 .find = mq_find, 280 .walk = mq_walk, 281 .dump = mq_dump_class, 282 .dump_stats = mq_dump_class_stats, 283 }; 284 285 struct Qdisc_ops mq_qdisc_ops __read_mostly = { 286 .cl_ops = &mq_class_ops, 287 .id = "mq", 288 .priv_size = sizeof(struct mq_sched), 289 .init = mq_init, 290 .destroy = mq_destroy, 291 .attach = mq_attach, 292 .dump = mq_dump, 293 .owner = THIS_MODULE, 294 }; 295